Homeostasis is the dynamic process where internal physical and chemical conditions are maintained within an optimal range promoting proper cellular function.
Body fluids and conditions that need to be monitored and maintained;
Internal temperature
blood glucose levels
blood pH
hormone levels
Internal environment: the extracellular fluid surrounding our cells and tissues, it also makes up the plasma portion of the blood
Interstitial fluid: the fluid surrounding the body cells / fills the spaces between our cells and tissues
Organ Systems Involved in Homeostasis
Nervous System: brain, spinal chord, peripheral nerves, sensory organs Endocrine System: pituitary gland, thyroid, adrenal, pancreas Muscular System: skeletal, cardiac, smooth muscle Integumentary System: skin, sweat glands, hair, nails Excretory System: kidneys, bladder, ureter, urethra Reproductive System: female organs (ovaries, oviducts, uterus, vagina, mammary glands), male organs (testes, sperm ducts, accessory glands, penis)
Out of all the systems involved, the endocrine and nervous systems are the most important
Feedback Mechanisms 9.2
Two types of feedback mechanisms;
Positive: the response of a system that acts to increase the effect of any changes made to the system
enhance the effect of a change in the internal or external environment
usually does not result in homeostasis
Labour contractions during child birth are good examples of positive feedback loops
uterine contractions (stimulus) detected by the pituitary gland release oxytocin
as the amount of oxytocin being released increases, uterine contractions increase, in turn more oxytocin is released and so on
Negative: the response of a system that acts to maintain equilibrium by compensating for any changes made to the system
responses to negative feedback loops may be physiological or behavioral
stimulus: environmental change
sensor: the element of a feedback system detecting changes in environment
integrator/control: compares present conditions to ideal conditions
effector: it acts to return the system to its optimal state
Another example of a negative feedback loop is a thermostat.
Tahrik Rodriques
January 6 2013
Homeostasis
Maintaining Internal Balance 9.1Homeostasis is the dynamic process where internal physical and chemical conditions are maintained within an optimal range promoting proper cellular function.
Body fluids and conditions that need to be monitored and maintained;
Internal environment: the extracellular fluid surrounding our cells and tissues, it also makes up the plasma portion of the blood
Organ Systems Involved in Homeostasis
Nervous System: brain, spinal chord, peripheral nerves, sensory organsEndocrine System: pituitary gland, thyroid, adrenal, pancreas
Muscular System: skeletal, cardiac, smooth muscle
Integumentary System: skin, sweat glands, hair, nails
Excretory System: kidneys, bladder, ureter, urethra
Reproductive System: female organs (ovaries, oviducts, uterus, vagina, mammary glands), male organs (testes, sperm ducts, accessory glands, penis)
Out of all the systems involved, the endocrine and nervous systems are the most important
Feedback Mechanisms 9.2
Two types of feedback mechanisms;
Labour contractions during child birth are good examples of positive feedback loops
stimulus: environmental change
sensor: the element of a feedback system detecting changes in environment
integrator/control: compares present conditions to ideal conditions
effector: it acts to return the system to its optimal state
Another example of a negative feedback loop is a thermostat.
http://www.youtube.com/watch?feature=player_embedded&v=DFyt7FJn-UM